In orthopedic bone repair procedures, a variety of devices and implants have been devised to stabilize a bone fracture or to space vertebrae or attach ligaments or tendons to bone.
Most of these devices require the use of threaded fasteners or screws that are driven into the bone and held or anchored in place to the bone.
The bone structure typically has a hard outer surface or shell commonly referred to as cortical bone and a softer interior of a more open celled spongy structure of cancellous bone. Accordingly, the fastener must be held in place taking into account the structure of the bone.
A variety of unique thread configurations for bone screws have been developed for this purpose, the goal being to provide a safe and reliable fastening into the bone material.
The present invention provides a unique and advantageous design to create secure attachment of a bone fastener. Loosening of the fastener and damaging the threads cut into the bone are primary limitations of prior art fasteners.
These and other limitations in the prior art have been corrected and solved by the present invention as disclosed herein.